Process and apparatus for producing hydroxids of metals by means of ammonia.



H. A. FRASCH.

PROCESS AND APPARATUS FOR PRODUCING HYDROXIDS 0F METALS E iY MEANS OF AMMONIA.

APPLICAHON FILED APR-10, 191s.

Patented Apr. 13, 1915.

Al/orney TED swamps ra rnn r oimibn.

HANS A. reason, or new roan, n. Y.

rnoonss AND APPARATUS roe PRODUCING nvnnoxnos or METALS BY Means or AMMONIA.

Specification of Letters Patent.

To all whom it may concern:

Be it known that l, HANS A. FRAscH, a

citizen of the United States, residing at New York, in the county of New York and State of New York, have invented a certain new and useful Improvement in Processes and Apparatus for Producing Hydroxide of Metals by Means of Ammonia, of which the following is a full, clear, and exact description.

This invention relates to the recovery of hydroxids of metals from their solution, and more particularly of metals whose hydroxids are soluble in ammonia and reactavith a salt of ammonia.

In order to illustrate myinvention I will describe it as applied in the production of the hydroxid. of nickel.

, It is well known that nickel ammonium chlorid or sulfate can be decomposed by water to nickel hydrate and ammonium chlorid or sulfate. The nickel hydrate obtained by this reaction, as well as by other well known methods, is of bulky and slimy nature and difficult to wash and separate frolnthe filtrate or liquid in which it is suspended. Further, during the evaporation and recovery of the ammonia by boiling, the nickel hydrate reacts with the ammomum chlorid and reverts to nickel chlorid and ammonia; and similar difficulties are experienced in every instance where the hydrate of a metal is precipitated from a solution of a salt of a metal by means of ammonia. My invention.

overcomes these difliculties, yielding heavy and granular oxids or hydrated oxids which render them of greater value for the production of pigments and carbonates; and in case of nickel, when the hydrate is used. for the production of alkali, such nickel hydrate reacts more promptly and assures higher yields of alkali. Besides, my invention permits precipitating by ammonia completely all the nickel or other metals which may be in a solution in much shorter time than other wise would be required, while atthe same time the ammonia may be recovered and again utilized.

Any suitable apparatus may be used for carrying out the process of this invention, and for illustration 1 have herein shown two forms of apparatus, without however thereby limiting the invention to mere details, since these may be varied within the requirements of the practice adopted.

In the accompanying drawings, illustrating the invention, in the two figures of which like parts are similarly designated, Figure 1 is a' diagrammatic vertical section of one such apparatus, and Fig. 2 is a similar view of another.

The still 1, its heating coil 2, and the condenser 3, may be of any approved construction. In the apparatus shown in Fig. 1, a dephlegmator column 4 is interposed between the still and condenser, and these three parts are in open communication. 5 is a catch-basin for the condenser. 6 is the sup ply pipe for the still. 7 are the water circulating pipes for the condenser, by which it may be kept at the desired temperature. 8 is a pipe for conveying away-from the con- ]Patented Apr. 13, 11911.5(

denser excess vapor, to another condenser, or

an absorber, or other vessel or receptacle, not shown. Pipe 8 is connected by pipe 9 with a circulating pump 10, and this pump is also connected by pipe 11 with the still. The

catch-basin 5 may be connected with that. portion of the pipe 11 which. enters the still;

by means of the pipe 12 and its valve 13, and. the valve 14; on the pump side of the pipe 11.

In the apparatus shown in Fig. 2, the still is connected 'ith the upper end of a primary condenser 15, by a pipe 16. This con denser is interposed between the still and the condenser 23 and connected to both. condenser 15 is a safety or back-pressure valve 17 by means of which the pressure in the still and condenser may be regulated. Condenser 15 has the pipe 18 opening into the still to return thereto the condenser fluid. The condenser 3 in this arrangement be.-

comes a secondary condenser. It has a bot tom connection 19 with a receptacle 20 to care for the reflux condensation, and also a side connection 21 with said receptacle to allow theair to escape from the receptacle to the condenser. The receptacle 20 is connectcd by the pipe 22 with pipe 23 leading into the still, and this pipe has valves 91- in it arranged upon opposite sides of the pipe 22. V I The condensed ammonlcal 11(11101. accumulating in the receptacle 20 may be utilized" during further operations and introduced into the still by Way of the pipes 22, 23, or it may be conducted through pipe 23 to an absorber and there utilized.

To carry out my invention, for example in recovering nickel hydrate from nickel chlorid, or nickel ammonium chlorid as practised in the manufacture of caustic Soda, I add the nickel salt to Water, or, as I prefer, tea solution of calcium chlorid 0011- reflux condensing system, as shown in Fig; 1,'Wh1ch I keep at a temperature toassuret sufficient condensation of ammonia in the reflux liquid to maintain the presence of a desired quantity. of ammonia in the distilling fluid, such as may be required by the nickel yet in solution in the fluid. In place of supplying the boiling fluid vvith ammonia by the return of reflux condensation, I may introduce into the boiling fluid ammonia in v the form of gas, or in any other form, coming from the distilling system, itself, or from an outside source. Again, I may conduct the boiling under pressure and thereby increase the amount of free ammonia retained in the boiling fluid, as shown in Fig. 9]. The boiling and addition of ammonia may be continued until all the nickel or any part thereof is precipitated. To supply the free ammonia 'to the boiling fluid, I may also add, continuously or periodically, any equivalent alkali which will react with the ammonium chlorid in quantities to assure the presence of a desired amount of free ammonia in the fluid.

While I select for purpose of illustration the recovery of nickel hydrate from nickelammonium chlorid, I do not limit the application of my invention to this particular compound. The invention may also be employed for recovery of nickel hydrate from other salts of nickel, such as the sulfate or nickel ammonium sulfate,-in Which case ammonium sulfate may be substituted for the chlorid. It may also be used in the productionof the hydrate from a solution of the salts of any other metal, such as lead, copper, cobalt, or iron.

To practice my invention in the apparatus of Fig. 1, I proceed as follows: Into the distilling vessel 1, which is supplied with steam coilsqil, I introduce through supply pipe 6 License a quantity of a solution of calcium chlorid containing ammonium chlorid and free ammonia, together with the nickel salt, or with a solution of any other salt of a metal from which the hydrate is to be obtained. Steam is then admitted to coil 2 and the contents ture existing in the catch-basin 5, passes on through pipe 8 for further condensation, if

necessar or to an absorber, to be there recovered in the usual manner and used again in further operations. The valve 13 being opened, part or all of the contents of the catch-basin 5 may be allowed to return to the still 1, thus supplying fresh quantities of ammonia to the contents of the still 1, at any time it may be desired; or the valve 13 may be so regulated that constantly and continuously a part only, and as much as is desired, of the ammoniacal liquor contained in the catch-basin returns to the still proper by Way of pipe 11, While the rest of the ainmoniacal liquor from the condenser and catch-basin flows over the catch-basin, or by a special conduit, through the dephlegmator 4., Where the ammonia is again volatilized. The boiling of the fluid in still 1 and addition of ammonia through pipe 11 is continued until all or as much of the nickel or other metal as is desired is precipitated. The valve 13 is then closed and the contents of the still 1 are removed through a suitable outlet and the hydrate is then separated from the still liquor by filtration or by any other Well-known means. The still liquor or filtrate may then be allowed to cool and the ammonium chlorid which Was formed during the operation, or as much of it as is desired, may be allowed to crystallize; or it may be treatedwhile yet hot with lime and returned to the process, the ammonia being recovered during the followin operation.

Insteac of supplying the still 1 with ammonia during the boiling process by means of the reflux condenser liquid, I may also close the overflow valve 13 and supply the ammonia to the still 1 in form of vapor from pipe 8 by means of the circulating pump 1.0, pipes 9 and 11, and valve lfl. This method of practising my invention is not limited to this particular apparatus, for,

as already stated, I may also conduct the boiling operation under pressure as shown in Fig. 2 and thereby retain in the boiling fluid in the still a greater amount of am monia than would be possible if the boiling were conducted at atmospheric pressure.

It is understood that the terms hy droxidf, and hydrate are interchange ammonia, by boiling in presence oil an am-' monium salt until the nickel oxid is precipitated While maintaining the solution alkaline with ammonia.

3. The method of precipitating nickel oxid from a solutionof nickelammonium chlorid, by boiling inpresence of a solution of ammonium chlorid until the nickel oxid is precipitated While maintaining the solution alkaline with ammonia.

4. In the process of producing hydrated oxidsbf metals by means of ammonia, boiling a solution of the salt of a desired metal in presence of a salt of ammonia and free ammonia, condensing the aqueous ammoniacal "apor evaporated during boiling and returning sufi icient of the condensate to keep the boiling solution alkaline While the oXid is'being precipitated.

5. In the process of producing hydrated oxids of metals by means of ammonia, boiling a solution of the salt ofa metal in presence of ammonium chlorid and free ammonia, concentrating the vaporized ammonia by means of dephlegmation, and remetals, boiling a solution of a salt of a desired metal in presence of a salt of ammonia and free ammonia under pressure, condensing more or less of the ammonia during boiling and returning sufficient of the condensate to the boiling solution to keep it alkaline.

'7. An apparatus for the precipitation of the hydroxids of metals from their solutions by means of ammonia, consisting of a distilling vessel and a condenser, a receptacle located between the distilling vessel and condenser and provided with an opening for the passage of the vapor, an outflow for the condenser fluid, and means to regulate the outflow and the return of the condenser fluid to the distilling vessel.

8. An apparatus for the precipitation of the hydroxids'of metals from their solutions by means of ammonia, consisting of a distilling vessel, a condenser, and a dephlegmating column provided with means to remove from the column all or parts of the return fluid coming from the condenser, and means to regulate the return of such fluid to the body of the distilling vessel.

9. An apparatus for the precipitation of the hydroigids of metals from their solutions by means of ammonia, consisting of a distilling vessel, a condenser, and a dephlegmating device provided with means to abstract ammonia gas from the apparatus, and means to return and introduce the ammonia gas into the body of the still.

In testimony whereof I have hereunto set my hand this 10th day of April A. D. 1913.

HANS A. FRASCH.

Witnesses War. H. Fmoniui, LILLIE M. PERRY. 

